Well after being gone for a while with Linux I decided to get back into it but it looks like I've forgotten more stuff then I thought.

I'm doing the initial install. I've got my partitions made but whenever I try to mkfs.ext2 /dev/sdb1 or mkfs.ext4 /dev/sdb3 I get the error "/dev/sbx is apparently in use by the system; will not make a filesystem here." I double checked that those are the correct partitions.

Well to be a little more detailed I'm following the X86 handbook for doing a Gentoo Install, I'm at the Installing Filesystem section and I'm getting the "Filesystem in use" error. I don't know why I'm getting it but I want to get past it.

Fdisk -l verifies that I'm using the correct partitions on the correct disk.

Did you already mount those partitions (or, if you're installing from some live environment, were they automatically mounted)?
Try "mount" without any parameters to see if they're mounted._________________Kali Ma
Now it's autumn of the aeons
Dance with your sword
Now it's time for the harvest

Very strange.
Do you access /dev/sdb with any other programme, like another instance of fdisk or gparted or something? That's all the ideas I have._________________Kali Ma
Now it's autumn of the aeons
Dance with your sword
Now it's time for the harvest

What I meant was if you were still running fdisk or gparted (in another terminal etc.) while trying to format the partitions._________________Kali Ma
Now it's autumn of the aeons
Dance with your sword
Now it's time for the harvest